data_global _chemical_name_mineral 'Brownmillerite' loop_ _publ_author_name 'Vanpeteghem C B' 'Angel R J' 'Zhao J' 'Ross N L' 'Redhammer G J' 'Seifert F' _journal_name_full 'Physics and Chemistry of Minerals' _journal_volume 35 _journal_year 2008 _journal_page_first 493 _journal_page_last 504 _publ_section_title ; The effect of oxygen vacancies and aluminium substitution on the high-pressure properties of brownmillerite-structured Ca2Fe2-xAlxO5 Note: x = 0.55 Note: P = 3.21 GPa ; _database_code_amcsd 0017773 _chemical_compound_source 'Synthetic' _chemical_formula_sum 'Ca2 (Fe1.45 Al.55) O5' _cell_length_a 5.3394 _cell_length_b 14.4853 _cell_length_c 5.5584 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 429.902 _exptl_crystal_density_diffrn 3.955 _symmetry_space_group_name_H-M 'I 2 m b' loop_ _space_group_symop_operation_xyz 'x,y,z' '1/2+x,1/2+y,1/2+z' 'x,1/2+y,-z' '1/2+x,+y,1/2-z' 'x,1/2-y,z' '1/2+x,-y,1/2+z' 'x,-y,-z' '1/2+x,1/2-y,1/2-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_occupancy _atom_site_U_iso_or_equiv Ca 0.48900 0.10824 0.02640 1.00000 0.00785 FeM 0.00000 0.00000 0.00000 0.87000 0.00659 AlM 0.00000 0.00000 0.00000 0.13000 0.00659 FeT 0.95200 0.25000 0.93020 0.58000 0.00621 AlT 0.95200 0.25000 0.93020 0.42000 0.00621 O1 0.24300 0.98530 0.25900 1.00000 0.00836 O2 0.02800 0.14200 0.07080 1.00000 0.01013 O3 0.61780 0.25000 0.87100 1.00000 0.00760